Type I and II interferon signatures in Sjogren's syndrome pathogenesis: Contributions in distinct clinical phenotypes and Sjogren's related lymphomagenesis

Update on the pathophysiology and treatment of primary Sjögren syndrome

Sjögren syndrome or Sjögren disease is a chronic form of autoimmune epithelitis characterized by lymphocytic infiltration of the exocrine glands, particularly the salivary and lacrimal glands, leading to progressive glandular dysfunction and subsequent xerostomia and xerophthalmia. Other common manifestations include pain and fatigue, various systemic manifestations and non-Hodgkin's lymphoma. Sjögren syndrome is therefore a complex and disabling disease associated with a reduced quality of life and with considerable long-term damage. Most of the available treatments are merely symptomatic with limited efficacy in both preventing glandular damage and suppressing systemic disease activity. In the past 10 years, great progress has been made in understanding the pathophysiology of Sjögren syndrome, opening new avenues towards a more targeted and individualized therapeutic approach to the disease. Indeed, several randomized controlled trials have just been completed or are poised to commence evaluating the effectiveness of novel drugs targeting both innate and adaptive immune pathways, including pro-inflammatory cytokines, the type I interferon system, B cell activation, B cell and T cell co-stimulation pathway, and ectopic germinal centre formation. Novel clinical trials are also ongoing exploring various targeted approaches (that is, IgG recycling inhibition, nuclease therapy and CAR-T cell therapy) for Sjögren syndrome.

Increased Interferon Signaling in Vaginal Tissue of Patients With Primary Sjögren Syndrome

OBJECTIVE

Vaginal dryness is an important factor influencing sexual function in women with primary Sjögren syndrome (pSS). Previous studies showed a higher degree of inflammation in vaginal biopsies from patients with pSS compared to non-pSS controls. However, the molecular pathways that drive this inflammation remain unclear. Therefore, the aim of this study was to investigate inflammatory pathway activity in the vaginal tissue of patients with pSS.

METHODS

Vaginal biopsies of 8 premenopausal patients with pSS experiencing vaginal dryness and 7 age-matched non-pSS controls were included. Expression of genes involved in inflammation and tissue homeostasis was measured using NanoString technology and validated using TaqMan Real-Time PCR. Vaginal tissue sections were stained by immunohistochemistry for myxovirus resistance protein 1 (MxA) and CD123 (plasmacytoid dendritic cells [pDCs]).

RESULTS

The most enriched pathway in vaginal biopsies from patients with pSS compared to non-pSS controls was the interferon (IFN) signaling pathway (P < 0.01). Pathway scores for Janus kinase and signal transducer and activator of transcription (JAK-STAT) and Notch signaling were also higher (P < 0.01 for both pathways). Conversely, transforming growth factor-β signaling and angiogenesis pathway scores were lower in pSS (P = 0.02 and P = 0.04, respectively). Differences in IFN signaling between patients with pSS and non-pSS controls were confirmed by PCR and MxA tissue staining. No CD123+ pDCs were detected in vaginal biopsies. IFN-stimulated gene expression levels correlated positively with CD45+ cell numbers in vaginal biopsies and serum anti-SSA/Ro positivity.

CONCLUSION

Upregulation of IFN signaling in vaginal tissue of women with pSS, along with its association with tissue pathology, suggests that IFNs contribute to inflammation of the vaginal wall and potentially also to clinical symptomatology (ie, vaginal dryness).

Association of B-cell activating factor gene variants with serum anti-JCV antibody positivity in male patients with multiple sclerosis under natalizumab treatment: Implications for progressive multifocal leukoencephalopathy risk stratification

INTRODUCTION

Progressive multifocal leukoencephalopathy (PML) is a potentially life-threatening complication among Multiple Sclerosis (MS) patients under natalizumab treatment, with serum anti-JCV antibody titers being used for stratification risk. Given the critical role of interferon (IFN)/B-cell activating factor (BAFF) axis in humoral immune responses against viruses, we explored whether it is involved in the generation of serum anti-JCV antibodies among these patients.

METHODS

162 consecutive patients with relapsing-remitting MS under natalizumab treatment were included. Serum anti-JCV antibodies were measured at baseline, as well as 12 and 24 months after treatment initiation. Type I and II IFN-inducible genes and BAFF expression were quantitated in peripheral blood by qRT-PCR. Moreover, BAFF rs9514828, rs1041569, and rs9514827 gene variants were assessed by RFLP-PCR.

RESULTS

While type I and II IFN inducible gene expression were not associated with anti-JCV serum titers, the latter were significantly correlated with BAFF gene expression. Of interest, the TTT haplotype of the studied BAFF variants was more frequently detected in male, but not female anti-JCV (+) MS patients compared to anti-JCV (-) counterparts at baseline, as well as at 12 months and 24 months of natalizumab treatment. Measures of clinical validity/utility for the BAFF TTT haplotype showed 88% specificity, 45%, positive predictive value, and sensitivity of 70% for the discrimination of anti-JCV (+) male MS patients after 24 months of treatment.

CONCLUSIONS

Our study suggests an implication of the BAFF axis in the production of serum anti-JCV antibodies. Additionally, the BAFF TTT haplotype derived from the rs9514828, rs1041569, and rs9514827 variants may represent a novel risk factor for anti-JCV seropositivity and indirectly for PML development among male MS patients treated with natalizumab.

Emerging biologic frontiers for Sjogren's syndrome: Unveiling novel approaches with emphasis on extra glandular pathology

Primary Sjögren's Syndrome (pSS) is a complex autoimmune disorder characterized by exocrine gland dysfunction, leading to dry eyes and mouth. Despite growing interest in biologic therapies for pSS, FDA approval has proven challenging due to trial complications. This review addresses the absence of a molecular-target-based approach to biologic therapy development and highlights novel research on drug targets and clinical trials. A literature search identified potential pSS treatment targets and recent advances in molecular understanding. Overlooking extraglandular symptoms like fatigue and depression is a notable gap in trials. Emerging biologic agents targeting cytokines, signal pathways, and immune responses have proven efficacy. These novel therapies could complement existing methods for symptom alleviation. Improved grading systems accounting for extraglandular symptoms are needed. The future of pSS treatment may involve gene, stem-cell, and tissue-engineering therapies. This narrative review offers insights into advancing pSS management through innovative biologic interventions.

Transcriptomic Profiling of Peripheral B Cells in Antibody Positive Sjogren's Patients Reveals Interferon Signature

BACKGROUND

Sjögren's disease (SjD) is a common systemic autoimmune disease that affects mainly women. Key pathologic features include the infiltration of exocrine glands by lymphocytes and the activation of B lymphocytes with the production of autoantibodies. We aimed to analyze the transcriptome of circulating B cells from patients with SJD and healthy controls to decipher the B-cell-specific contribution to SJD.

METHODS

RNA from peripheral blood B cells of five untreated female patients with SjD and positive ANA, positive anti-SSA (both Ro-52 and Ro-60), positive anti-SSB and positive rheumatoid-factor, and five healthy controls was subjected to whole-transcriptome sequencing. A false discovery rate of < 0.1 was applied to define differentially expressed genes (DEG).

RESULTS

RNA-sequencing identified 56 up and 23 down DEG. Hierarchal clustering showed a clear separation between the two groups. Ingenuity pathway analysis revealed that these genes may play a role in interferon signaling, chronic mycobacterial infection, and transformation to myeloproliferative disorders.

CONCLUSIONS

We found upregulated expression of type-I and type-II interferon (IFN)-induced genes, as well as genes that may contribute to other concomitant conditions, including infections and a higher risk of myeloproliferative disorders. This adds insight into the autoimmune process and suggests potential targets for future functional and prognostic studies.

Proteasome disorders and inborn errors of immunity

Inborn errors of immunity (IEI) or primary immune deficiencies (PIDD) are caused by variants in genes encoding for molecules that are relevant to the innate or adaptive immune response. To date, defects in more than 450 different genes have been identified as causes of IEI, causing a constellation of heterogeneous clinical manifestations ranging from increased susceptibility to infection, to autoimmunity or autoinflammation. IEI that are mainly characterized by autoinflammation are broadly classified according to the inflammatory pathway that they predominantly perturb. Among autoinflammatory IEI are those characterized by the transcriptional upregulation of type I interferon genes and are referred to as interferonopathies. Within the spectrum of interferonopathies, genetic defects that affect the proteasome have been described to cause autoinflammatory disease and represent a growing area of investigation. This review is focused on describing the clinical, genetic, and molecular aspects of IEI associated with mutations that affect the proteasome and how the study of these diseases has contributed to delineate therapeutic interventions.

Sjögren's syndrome

Sjögren's syndrome (SS) is characterised as keratoconjunctivitis sicca (dry eyes), xerostomia (dry mouth) commonly associated with salivary gland enlargement, and is referred to as Primary Sjögren's syndrome. It is known as Secondary Sjögren's syndrome when it occurs in patients, with connective tissue disease, such as rheumatoid arthritis, systemic lupus erythematosus, polyarthritis nodosa, polymyositis, and systemic sclerosis. SS has also been associated with chronic graft-versus-host disease after allogeneic bone marrow transplantation, human immunodeficiency syndrome (AIDS), hepatitis C infection (HCV), chronic biliary cirrhosis, neoplastic and myeloplastic syndromes, fibromyalgia, and chronic fatigue syndrome.

Association of endometriosis with Sjögren's syndrome: Genetic insights (Review)

Patients with a history of endometriosis have an increased risk of developing various autoimmune diseases such as rheumatoid arthritis, ankylosing spondylitis, systemic lupus erythematosus, multiple sclerosis and celiac disease. There is a potential association between endometriosis and an increased susceptibility for Sjögren's syndrome (SS). SS is a common chronic, inflammatory, systemic, autoimmune, multifactorial disease of complex pathology, with genetic, epigenetic and environmental factors contributing to the development of this condition. It occurs in 0.5‑1% of the population, is characterized by the presence of ocular dryness, lymphocytic infiltrations and contributes to neurological, gastrointestinal, vascular and dermatological manifestations. Endometriosis is an inflammatory, estrogen‑dependent, multifactorial, heterogeneous gynecological disease, affecting ≤10% of reproductive‑age women. It is characterized by the occurrence of endometrial tissue outside the uterine cavity, mainly in the pelvic cavity, and is associated with pelvic pain, dysmenorrhea, deep dyspareunia and either subfertility or infertility. It is still unclear whether SS appears as a secondary response to endometriosis, or it is developed due to any potential shared mechanisms of these conditions. The aim of the present review was to explore further the biological basis only of the co‑occurrence of these disorders but not their association at clinical basis, focusing on the analysis of the partially shared genetic background between endometriosis and SS, and the clarification of the possible similarities in the underlying pathogenetic mechanisms and the relevant molecular pathways.

Loss of STIM1 and STIM2 in salivary glands disrupts ANO1 function but does not induce Sjogren's disease

Sjogren's disease (SjD) is an autoimmune disease characterized by xerostomia (dry mouth), lymphocytic infiltration into salivary glands and the presence of SSA and SSB autoantibodies. Xerostomia is caused by hypofunction of the salivary glands and has been involved in the development of SjD. Saliva production is regulated by parasympathetic input into the glands initiating intracellular Ca 2+ signals that activate the store operated Ca 2+ entry (SOCE) pathway eliciting sustained Ca 2+ influx. SOCE is mediated by the STIM1 and STIM2 proteins and the ORAI1 Ca 2+ channel. However, there are no studies on the effects of lack of STIM1/2 function in salivary acini in animal models and its impact on SjD. Here we report that male and female mice lacking Stim1 and Stim2 ( Stim1/2 K14Cre ) in salivary glands showed reduced intracellular Ca 2+ levels via SOCE in parotid acini and hyposalivate upon pilocarpine stimulation. Bulk RNASeq of the parotid glands of Stim1/2 K14Cre mice showed a decrease in the expression of Stim1/2 but no other Ca 2+ associated genes mediating saliva fluid secretion. SOCE was however functionally required for the activation of the Ca 2+ activated chloride channel ANO1. Despite hyposalivation, ageing Stim1/2 K14Cre mice showed no evidence of lymphocytic infiltration in the glands or elevated levels of SSA or SSB autoantibodies in the serum, which may be linked to the downregulation of the toll-like receptor 8 ( Tlr8 ). By contrast, salivary gland biopsies of SjD patients showed increased STIM1 and TLR8 expression, and induction of SOCE in a salivary gland cell line increased the expression of TLR8 . Our data demonstrate that SOCE is an important activator of ANO1 function and saliva fluid secretion in salivary glands. They also provide a novel link between SOCE and TLR8 signaling which may explain why loss of SOCE does not result in SjD.

GZMK+CD8+ T cells Target a Specific Acinar Cell Type in Sjögren's Disease

Sjögren's Disease (SjD) is a systemic autoimmune disease without a clear etiology or effective therapy. Utilizing unbiased single-cell and spatial transcriptomics to analyze human minor salivary glands in health and disease we developed a comprehensive understanding of the cellular landscape of healthy salivary glands and how that landscape changes in SjD patients. We identified novel seromucous acinar cell types and identified a population of PRR4+CST3+WFDC2- seromucous acinar cells that are particularly targeted in SjD. Notably, GZMK+CD8 T cells, enriched in SjD, exhibited a cytotoxic phenotype and were physically associated with immune-engaged epithelial cells in disease. These findings shed light on the immune response's impact on transitioning acinar cells with high levels of secretion and explain the loss of this specific cell population in SjD. This study explores the complex interplay of varied cell types in the salivary glands and their role in the pathology of Sjögren's Disease.

Type-I interferon pathway and DNA damage accumulation in peripheral blood of patients with psoriatic arthritis

Objectives

The abnormal DNA damage response is associated with upregulation of the type-1 interferon (IFN-I) pathway in certain rheumatic diseases. We investigated whether such aberrant mechanisms operate in psoriatic arthritis (PsA).

Methods

DNA damage levels were measured by alkaline comet assay in peripheral blood mononuclear cells from 52 PsA patients and age-sex-matched healthy individuals. RNA expression of IFIT1, MX1 and IFI44, which are selectively induced by IFN-I, was quantitated by real-time polymerase chain reaction and their composite normalized expression resulted in IFN-I score calculation. RNA expression of IL1β, IL6, TNF, IL17A and IL23A was also assessed in PsA and control subgroups.

Results

In PsA, DNA damage accumulation was increased by almost two-fold compared to healthy individuals (olive tail moment arbitrary units, mean ± SD; 9.42 ± 2.71 vs 4.88 ± 1.98, p<0.0001). DNA damage levels significantly correlated with serum C-Reactive-protein and IL6 RNA expression in PBMCs. Despite increased DNA damage, the IFN-I score was strikingly lower in PsA patients compared to controls (-0.49 ± 6.99 vs 4.24 ± 4.26; p<0.0001). No correlation was found between IFN-I pathway downregulation and DNA damage. However, the IFN-I score in a PsA subgroup was lower in those patients with higher IL1β expression, as well as in those with higher TNF/IL23A PBMCs expression.

Conclusion

DNA damage in PsA correlates with measures of inflammation but is not associated with the IFN-I pathway induction. The unexpected IFN-I downregulation, albeit reminiscent to findings in experimental models of spondyloarthritis, may be implicated in PsA pathogenesis and explained by operation of other cytokines.

B-cell activating factor gene variants in multiple sclerosis: Possible associations with disease susceptibility among females

Although B cells and B cell activating factor (BAFF) have been previously implicated in MS pathogenesis, data regarding the genetic influence of BAFF polymorphisms on MS susceptibility are limited. Here we aim to explore whether BAFF polymorphisms could contribute to MS susceptibility. 156 RRMS patients fulfilling the revised McDonald criteria for MS diagnosis and 220 HCs were enrolled. Clinical, laboratory, and imaging characteristics were recorded. BAFF rs9514827, rs1041569, and rs9514828 polymorphisms were assessed by RFLP-PCR in DNA samples extracted from whole peripheral blood. The BAFF rs1041569 TT genotype along with the CTT and TTC haplotypes were associated with significantly increased risk for MS development in female MS patients compared to healthy female counterparts. These findings were not confirmed in males. The rs1041569 BAFF variant together with the CTT and TTC BAFF haplotypes derived from the BAFF rs9514827, rs1041569, and rs9514828 polymorphisms may represent novel genetic contributors to the development of MS in females.

The role and application of three IFN-related reactions in psoriasis

The pathophysiology of psoriasis is a highly complicated one. Due to the disease's specificity, it not only affects the patient's skin negatively but also manifests systemic pathological changes. These clinical symptoms seriously harm the patient's physical and mental health. IFN, a common immunomodulatory factor, has been increasingly demonstrated to have a significant role in the development of psoriatic skin disease. Psoriasis is connected with a variety of immunological responses. New targets for the therapy of autoimmune skin diseases may emerge from further research on the mechanics of the associated IFN upstream and downstream pathways. Different forms of IFNs do not behave in the same manner in psoriasis, and understanding how different types of IFNs are involved in psoriasis may provide a better notion for future research. This review focuses on the involvement of three types of IFNs in psoriasis and related therapeutic investigations, briefly describing the three IFNs' production and signaling, as well as the dual effects of IFNs on the skin. It is intended that it would serve as a model for future research.

A bibliometric analysis of primary Sjögren's syndrome-associated lymphoma from 1991 to 2022

Background

Patients with primary Sjögren's syndrome (pSS) take a higher risk of developing lymphoma, which is the most frequent cause of death in pSS. Based on this situation, the number of publications focusing on pSS-associated lymphoma has been growing. Nevertheless, the extent, range, and nature of available research in this field have not been systematically summarized. This study aimed to map the literature available on pSS-associated lymphoma and identify global hotspots and trends.

Methods

Papers on pSS and lymphoma published from 1991 to 2022 were searched from the Web of Science Core Collection. Microsoft Excel, SPSS Statistics, VOSviewer, and CiteSpace software were used to analyze and visualize the quantity and citations of publications, and the global research hotspots and trends of pSS-associated lymphoma.

Results

629 publications from 50 countries/regions and 538 institutions were included in this study. From 1991 to 2022, the cumulative publications steadily increased. The USA ranked first in the number of publications (n = 118, 18.76 %), followed by Italy (n = 94, 14.94 %) and France (n = 73, 11.61 %). Udine University (n = 29) and Salvatore De Vita (n = 39) were the most prolific affiliation and author, respectively. Claudio Vitali was the most frequently cited author (n = 335). In total, the most frequently occurring keywords were clustered into four well-defined groups. The first group of keywords pointed to the clinical assessment and treatment of pSS-associated lymphoma. The second group highlighted the pathogenesis. The third group identified the predictors and prognosis of pSS-associated Lymphoma, while the fourth group focused on interstitial lung disease and pulmonary lymphoma in patients with pSS. Currently, the hot keywords include consensus, disease activity, and pathogenesis. Ultrasonography, mucosa-associated lymphoid tissue (MALT) lymphoma, and epidemiology are the emerging research trends in pSS-associated lymphoma.

Conclusion

Research on pSS-associated lymphoma is burgeoning. Despite clinical assessment, treatment and pathogenesis, researchers also showed great interest in the predictors, prognosis, and pulmonary manifestations of pSS-associated lymphoma. Current research of pSS-associated lymphoma mainly focuses on consensus, disease activity, and pathogenesis, while the emerging research trends in pSS are pointing to ultrasonography, MALT lymphoma and epidemiology.

Causal associations of Sjögren's syndrome with cancers: a two-sample Mendelian randomization study

BACKGROUND

Several observational studies have explored the associations between Sjögren's syndrome (SS) and certain cancers. Nevertheless, the causal relationships remain unclear. Mendelian randomization (MR) method was used to investigate the causality between SS and different types of cancers.

METHODS

We conducted the two-sample Mendelian randomization with the public genome-wide association studies (GWASs) summary statistics in European population to evaluate the causality between SS and nine types of cancers. The sample size varies from 1080 to 372,373. The inverse variance weighted (IVW) method was used to estimate the causal effects. A Bonferroni-corrected threshold of P < 0.0031 was considered significant, and P value between 0.0031 and 0.05 was considered to be suggestive of an association. Sensitivity analysis was performed to validate the causality. Moreover, additional analysis was used to assess the associations between SS and well-accepted risk factors of cancers.

RESULTS

After correcting the heterogeneity and horizontal pleiotropy, the results indicated that patients with SS were significantly associated with an increased risk of lymphomas (odds ratio [OR] = 1.0010, 95% confidence interval [CI]: 1.0005-1.0015, P = 0.0002) and reduced risks of prostate cancer (OR = 0.9972, 95% CI: 0.9960-0.9985, P = 2.45 × 10-5) and endometrial cancer (OR = 0.9414, 95% CI: 0.9158-0.9676, P = 1.65 × 10-5). Suggestive associations were found in liver and bile duct cancer (OR = 0.9999, 95% CI: 0.9997-1.0000, P = 0.0291) and cancer of urinary tract (OR = 0.9996, 95% CI: 0.9992-1.0000, P = 0.0281). No causal effect of SS on other cancer types was detected. Additional MR analysis indicated that causal effects between SS and cancers were not mediated by the well-accepted risk factors of cancers. No evidence of the causal relationship was observed for cancers on SS.

CONCLUSIONS

SS had significant causal relationships with lymphomas, prostate cancer, and endometrial cancer, and suggestive evidence of association was found in liver and bile duct cancer and cancer of urinary tract, indicating that SS may play a vital role in the incidence of these malignancies.

Type I Interferons in Autoimmunity: Implications in Clinical Phenotypes and Treatment Response

Type I interferon (IFN-I) is thought to play a role in many systemic autoimmune diseases. IFN-I pathway activation is associated with pathogenic features, including the presence of autoantibodies and clinical phenotypes such as more severe disease with increased disease activity and damage. We will review the role and potential drivers of IFN-I dysregulation in 5 prototypic autoimmune diseases: systemic lupus erythematosus, dermatomyositis, rheumatoid arthritis, primary Sjögren syndrome, and systemic sclerosis. We will also discuss current therapeutic strategies that directly or indirectly target the IFN-I system.

Inhibition of JAK-STAT pathway corrects salivary gland inflammation and interferon driven immune activation in Sjögren's Disease

Objectives

Inflammatory cytokines that signal through the JAK- STAT pathway, especially interferons (IFNs), are implicated in Sjögren's Disease (SjD). Although inhibition of JAKs is effective in other autoimmune diseases, a systematic investigation of IFN-JAK-STAT signaling and effect of JAK inhibitor (JAKi) therapy in SjD-affected human tissues has not been reported.

Methods

Human minor salivary glands (MSGs) and peripheral blood mononuclear cells (PBMCs) were investigated using bulk or single cell (sc) RNA sequencing (RNAseq), immunofluorescence microscopy (IF), and flow cytometry. Ex vivo culture assays on PBMCs and primary salivary gland epithelial cell (pSGEC) lines were performed to model changes in target tissues before and after JAKi.

Results

RNAseq and IF showed activated JAK-STAT pathway in SjD MSGs. Elevated IFN-stimulated gene (ISGs) expression associated with clinical variables (e.g., focus scores, anti-SSA positivity). scRNAseq of MSGs exhibited cell-type specific upregulation of JAK-STAT and ISGs; PBMCs showed similar trends, including markedly upregulated ISGs in monocytes. Ex vivo studies showed elevated basal pSTAT levels in SjD MSGs and PBMCs that were corrected with JAKi. SjD-derived pSGECs exhibited higher basal ISG expressions and exaggerated responses to IFNβ, which were normalized by JAKi without cytotoxicity.

Conclusions

SjD patients' tissues exhibit increased expression of ISGs and activation of the JAK-STAT pathway in a cell type-dependent manner. JAKi normalizes this aberrant signaling at the tissue level and in PBMCs, suggesting a putative viable therapy for SjD, targeting both glandular and extraglandular symptoms. Predicated on these data, a Phase Ib/IIa randomized controlled trial to treat SjD with tofacitinib was initiated.

Exploring the shared molecular mechanisms between systemic lupus erythematosus and primary Sjögren's syndrome based on integrated bioinformatics and single-cell RNA-seq analysis

Background

Systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS) are common systemic autoimmune diseases that share a wide range of clinical manifestations and serological features. This study investigates genes, signaling pathways, and transcription factors (TFs) shared between SLE and pSS.

Methods

Gene expression profiles of SLE and pSS were obtained from the Gene Expression Omnibus (GEO). Weighted gene co-expression network analysis (WGCNA) and differentially expressed gene (DEG) analysis were conducted to identify shared genes related to SLE and pSS. Overlapping genes were then subject to Gene Ontology (GO) and protein-protein interaction (PPI) network analyses. Cytoscape plugins cytoHubba and iRegulon were subsequently used to screen shared hub genes and predict TFs. In addition, gene set variation analysis (GSVA) and CIBERSORTx were used to calculate the correlations between hub genes and immune cells as well as related pathways. To confirm these results, hub genes and TFs were verified in microarray and single-cell RNA sequencing (scRNA-seq) datasets.

Results

Following WGCNA and limma analysis, 152 shared genes were identified. These genes were involved in interferon (IFN) response and cytokine-mediated signaling pathway. Moreover, we screened six shared genes, namely IFI44L, ISG15, IFIT1, USP18, RSAD2 and ITGB2, out of which three genes, namely IFI44L, ISG15 and ITGB2 were found to be highly expressed in both microarray and scRNA-seq datasets. IFN response and ITGB2 signaling pathway were identified as potentially relevant pathways. In addition, STAT1 and IRF7 were identified as common TFs in both diseases.

Conclusion

This study revealed IFI44L, ISG15 and ITGB2 as the shared genes and identified STAT1 and IRF7 as the common TFs of SLE and pSS. Notably, the IFN response and ITGB2 signaling pathway played vital roles in both diseases. Our study revealed common pathogenetic characteristics of SLE and pSS. The particular roles of these pivotal genes and mutually overlapping pathways may provide a basis for further mechanistic research.

Leflunomide/hydroxychloroquine combination therapy targets type I IFN-associated proteins in patients with Sjögren's syndrome that show potential to predict and monitor clinical response

OBJECTIVES

To assess to what extent leflunomide (LEF) and hydroxychloroquine (HCQ) therapy in patients with primary Sjögren's syndrome (RepurpSS-I) targets type I IFN-associated responses and to study the potential of several interferon associated RNA-based and protein-based biomarkers to predict and monitor treatment.

METHODS

In 21 patients treated with LEF/HCQ and 8 patients treated with placebo, blood was drawn at baseline, 8, 16 and 24 weeks. IFN-signatures based on RNA expression of five IFN-associated genes were quantified in circulating mononuclear cells and in whole blood. MxA protein levels were measured in whole blood, and protein levels of CXCL10 and Galectin-9 were quantified in serum. Differences between responders and non-responders were assessed and receiver operating characteristic analysis was used to determine the capacity of baseline expression and early changes (after 8 weeks of treatment) in biomarkers to predict treatment response at the clinical endpoint.

RESULTS

IFN-signatures in peripheral blood mononuclear cell and whole blood decreased after 24 weeks of LEF/HCQ treatment, however, changes in IFN signatures only poorly correlated with changes in disease activity. In contrast to baseline IFN signatures, baseline protein concentrations of galectin-9 and decreases in circulating MxA and Galectin-9 were robustly associated with clinical response. Early changes in serum Galectin-9 best predicted clinical response at 24 weeks (area under the curve 0.90).

CONCLUSIONS

LEF/HCQ combination therapy targets type-I IFN-associated proteins that are associated with strongly decreased B cell hyperactivity and disease activity. IFN-associated Galectin-9 is a promising biomarker for treatment prediction and monitoring in pSS patients treated with LEF/HCQ.

Outline of Salivary Gland Pathogenesis of Sjögren's Syndrome and Current Therapeutic Approaches

Sjögren's syndrome (SS) is an autoimmune disease characterized by the involvement of exocrine glands such as the salivary and lacrimal glands. The minor salivary glands, from which tissue samples may be obtained, are important for the diagnosis, evaluation of therapeutic efficacy, and genetic analyses of SS. In the onset of SS, autoantigens derived from the salivary glands are recognized by antigen-presenting dendritic cells, leading to the activation of T and B cells, cytokine production, autoantibody production by plasma cells, the formation of ectopic germinal centers, and the destruction of salivary gland epithelial cells. A recent therapeutic approach with immune checkpoint inhibitors for malignant tumors enhances the anti-tumor activity of cytotoxic effector T cells, but also induces SS-like autoimmune disease as an adverse event. In the treatment of xerostomia, muscarinic agonists and salivary gland duct cleansing procedure, as well as sialendoscopy, are expected to ameliorate symptoms. Clinical trials on biological therapy to attenuate the hyperresponsiveness of B cells in SS patients with systemic organ involvement have progressed. The efficacy of treatment with mesenchymal stem cells and chimeric antigen receptor T cells for SS has also been investigated. In this review, we will provide an overview of the pathogenesis of salivary gland lesions and recent trends in therapeutic approaches for SS.

The Spectrum of Extraglandular Manifestations in Primary Sjögren's Syndrome

Extraglandular manifestations (EGMs) in primary Sjogren's syndrome (pSS) represent the clinical expression of the systemic involvement in this disease. EGMs are characterized by a wide heterogeneity; virtually any organ or system can be affected, with various degrees of dysfunction. The existing gaps of knowledge in this complex domain of extraglandular extension in pSS need to be overcome in order to increase the diagnostic accuracy of EGMs in pSS. The timely identification of EGMs, as early as from subclinical stages, can be facilitated using highly specific biomarkers, thus preventing decompensated disease and severe complications. To date, there is no general consensus on the diagnostic criteria for the wide range of extraglandular involvement in pSS, which associates important underdiagnosing of EGMs, subsequent undertreatment and progression to severe organ dysfunction in these patients. This review article presents the most recent basic and clinical science research conducted to investigate pathogenic mechanisms leading to EGMs in pSS patients. In addition, it presents the current diagnostic and treatment recommendations and the trends for future therapeutic strategies based on personalized treatment, as well as the latest research in the field of diagnostic and prognostic biomarkers for extraglandular involvement in pSS.

The Role of Myositis-Specific and Myositis-Associated Autoantibodies and the Activation of Type I Interferon Pathway in the Generation of Clinical Phenotypes of Inflammatory Myopathies

Idiopathic inflammatory myopathies (IIMs) are a group of heterogeneous autoimmune diseases with a prevalence of 20 cases per 100000 of population. Despite their diversity, IMMs are characterised by several common clinical features such as muscle inflammation, proximal muscle weakness, abnormal electromyography and/or muscle biopsy. Over the last years, it has been increasingly recognised that an array of autoantibodies known as myositis-specific antibodies (MSAs) and myositis-associated antibodies (MAAs) are associated with distinct clinical phenotypes and diverse prognosis. Although the exact underlying mechanism of IIMs is not fully understood, accumulating data suggest that the activation of type I interferon pathway plays a central role in disease development. Previous studies have reported the upregulation of type I interferon (IFN) induced genes in peripheral blood and muscle biopsies derived from myositis patients. Given the heterogeneity of inflammatory myopathies along with the central role of type I IFN pathway in disease pathogenesis, the aim of the current study is to elucidate the link between distinct clinical phenotypes of inflammatory myopathies with the presence of serum MSAs or MAAs, as well as with type I IFN activation.

Chronic Epstein-Barr virus infection: A potential junction between primary Sjögren's syndrome and lymphoma

Primary Sjögren's syndrome (pSS) is an autoimmune disease that targets exocrine glands, leading to exocrine dysfunction. Due to its propensity to infect epithelial and B cells, Epstein-Barr virus (EBV) is hypothesized to be related with pSS. Through molecular mimicry, the synthesis of specific antigens, and the release of inflammatory cytokines, EBV contributes to the development of pSS. Lymphoma is the most lethal outcome of EBV infection and the development of pSS. As a population-wide virus, EBV has had a significant role in the development of lymphoma in people with pSS. In the review, we will discuss the possible causes of the disease.

Emerging treatment for Sjögren's disease: a review of recent phase II and III trials

INTRODUCTION

Sjögren's Disease, SjD, is a systemic autoimmune disorder characterized by reduced function of the salivary and lacrimal glands. Patients suffer from dryness, fatigue, and pain and may present with or without extra-glandular organ involvement. Symptoms limit SjD patients' quality of life and are the most difficult to improve with therapy. SjD patients are heterogeneous and clustering them into biologically similar subgroups might improve the efficacy of therapies. The need for therapies that address both the symptoms and extra glandular organ involvement of SjD presents an unmet opportunity that has recently attracted a growing interest in the pharmaceutical industry.

AREAS COVERED

The goal of this report is to review recent phase II/III studies in SjD. To accomplish our goal, we performed a literature search for phase II/III studies and abstracts recently presented at conferences.

EXPERT OPINION

This review allows updates the reader on the multitude of recent phase II/III clinical trials. We speculate on how subtypes of SjD will drive future therapeutic targeting and inform pathogenesis.

The interferon in idiopathic inflammatory myopathies: Different signatures and new therapeutic perspectives. A literature review

Idiopathic inflammatory myopathies (IIM), even though sharing common clinical manifestations, are characterized by diversified molecular pathogenetic mechanisms which may account for the partial inefficacy of currently used immunomodulatory drugs. In the last decades, the role of interferon (IFN) in IIM has been extensively elucidated thanks to genomic and proteomic studies which have assessed the molecular signature at the level of affected tissues or in peripheral blood across distinct IIM subtypes. A predominant type I IFN response has been shown in dermatomyositis (DM), being especially enhanced in MDA5+ DM, while a type 2 IFN profile characterizes anti-synthetase syndrome (ASyS) and inclusion body myositis (IBM); conversely, a less robust IFN footprint has been defined for immune-mediated necrotizing myopathy (IMNM). Intracellular IFN signaling is mediated by the janus kinase/signal transducer and activator of transcription (JAK/STAT) through dedicated transmembrane receptors and specific cytoplasmic molecular combinations. These results may have therapeutic implications and led to evaluating the efficacy of new targeted drugs such as the recently introduced janus kinase inhibitors (JAKi), currently approved for the treatment of rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. In this review we aim to summarize the most significant evidence of IFN role in IIM pathogenesis and to describe the current state of the art about the ongoing clinical trials on IFN-targeting drugs, with particular focus on JAKi.

Impaired kynurenine metabolism in patients with primary Sjögren's syndrome

OBJECTIVES

Primary Sjögren's syndrome (pSS) is an autoinflammatory disease characterized by inflammation of the exocrine glands. Elevated inflammation causes an increase in kynurenine pathway (KP) metabolite levels by activating indoleamine 2,3-dioxygenase (IDO). The aim of this study was to measure serum KP metabolite concentrations in patients with pSS and to evaluate the relationship between these metabolites with disease activity score and clinical manifestations.

DESIGN & METHODS

A total of 80 patients with pSS and 80 healthy controls were enrolled in this study. Serum tryptophan (TRP), kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxyanthranilic acid (3HAA), 3-hydroxykynurenine (3HK), quinolinic acid (QUIN) concentrations were quantified with liquid chromatography with tandem mass spectrometry (LC-MS/MS). Demographic characteristics, clinical manifestations and disease activity score (ESSDAI) of the participants were recorded.

RESULTS

The serum level of KYN and QUIN were significantly higher in patients with pSS with low and moderate activity compared those healthy controls, while the serum level of TRP, KYNA/KYN and 3HK/KYN were lower. In addition, the significant difference for the serum level of KYNA was only in patients with moderate activity from healthy controls, and the difference was higher in favor of pSS patients. Moreover, the KYN/TRP levels were significantly increased with disease activity. The ESSDAI score was positively correlated with KYN/TRP ratio, but negatively correlated with KYNA/KYN ratio.

CONCLUSIONS

These findings indicated that KP metabolites may play a role in the etiopathogenesis, activation and progression of pSS.

Multiple fibrotic lung nodules in a patient with primary Sjögren's syndrome

Evaluation of bilateral lung nodules noted on imaging poses a diagnostic challenge to clinicians as it can have many differentials from benign to malignant causes. It becomes especially critical to identify them right when there are underlying autoimmune conditions and risk factors for infection. However, a thorough investigation can lead to the recognition of rare associations as described below. We present here a 57-year-old woman who was admitted to the hospital with shortness of breath. Imaging with a computed tomography (CT) scan showed that she had 8 bilateral cystic pulmonary nodules with focal areas of ground-glass opacity and mediastinal lymphadenopathy. Fibrobronchoscopy and histopathological studies were done on the right middle lobe lung nodule demonstrated that the lung nodule was fibrotic with reactive inflammation but showed no malignant cells. Upon further detailed history and chart review, it was noted that the patient had a history of dry eyes leading to an autoimmune workup showing positive antinuclear antibodies (ANA), anti-Ro, and anti-La antibodies with no follow-up since then. This lead to the suspicion that these nodules could be related to underlying Sjögren's syndrome. Initial inpatient management with intravenous steroids showed significant improvement in her symptomatology. Hence, we present this rare association of lung nodules with Sjögren's syndrome and its management for awareness of this condition.

Type I interferon pathway assays in studies of rheumatic and musculoskeletal diseases: a systematic literature review informing EULAR points to consider

OBJECTIVES

To systematically review the literature for assay methods that aim to evaluate type I interferon (IFN-I) pathway activation and to harmonise-related terminology.

METHODS

Three databases were searched for reports of IFN-I and rheumatic musculoskeletal diseases. Information about the performance metrics of assays measuring IFN-I and measures of truth were extracted and summarised. A EULAR task force panel assessed feasibility and developed consensus terminology.

RESULTS

Of 10 037 abstracts, 276 fulfilled eligibility criteria for data extraction. Some reported more than one technique to measure IFN-I pathway activation. Hence, 276 papers generated data on 412 methods. IFN-I pathway activation was measured using: qPCR (n=121), immunoassays (n=101), microarray (n=69), reporter cell assay (n=38), DNA methylation (n=14), flow cytometry (n=14), cytopathic effect assay (n=11), RNA sequencing (n=9), plaque reduction assay (n=8), Nanostring (n=5), bisulphite sequencing (n=3). Principles of each assay are summarised for content validity. Concurrent validity (correlation with other IFN assays) was presented for n=150/412 assays. Reliability data were variable and provided for 13 assays. Gene expression and immunoassays were considered most feasible. Consensus terminology to define different aspects of IFN-I research and practice was produced.

CONCLUSIONS

Diverse methods have been reported as IFN-I assays and these differ in what elements or aspects of IFN-I pathway activation they measure and how. No 'gold standard' represents the entirety of the IFN pathway, some may not be specific for IFN-I. Data on reliability or comparing assays were limited, and feasibility is a challenge for many assays. Consensus terminology should improve consistency of reporting.

Autoimmune epithelitis in primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is characterized by an autoimmune epithelitis associated with chronic inflammation of the exocrine glands. Alterations of extra-glandular functions in pSS is associated with lymphocytic infiltrates that invade the epithelial structures of affected organs. Within epithelial tissue, the expression of class II major histocompatibility complexes and costimulatory molecules by epithelial cells acting as non-professional antigen presenting cells, leads to the activation of T and B lymphocytes through multiple cellular crosstalk pathways. Although the pathogenetic mechanisms underlying pSS have not yet been elucidated, it is accepted that glandular epithelial cells are central regulators of the local autoimmune response.

Association between type I interferon pathway activation and clinical outcomes in rheumatic and musculoskeletal diseases: a systematic literature review informing EULAR points to consider

BACKGROUND

Type I interferons (IFN-I) contribute to a broad range of rheumatic and musculoskeletal diseases (RMDs). Compelling evidence suggests that the measurement of IFN-I pathway activation may have clinical value. Although several IFN-I pathway assays have been proposed, the exact clinical applications are unclear. We summarise the evidence on the potential clinical utility of assays measuring IFN-I pathway activation.

METHODS

A systematic literature review was conducted across three databases to evaluate the use of IFN-I assays in diagnosis and monitor disease activity, prognosis, response to treatment and responsiveness to change in several RMDs.

RESULTS

Of 366 screened, 276 studies were selected that reported the use of assays reflecting IFN-I pathway activation for disease diagnosis (n=188), assessment of disease activity (n=122), prognosis (n=20), response to treatment (n=23) and assay responsiveness (n=59). Immunoassays, quantitative PCR (qPCR) and microarrays were reported most frequently, while systemic lupus erythematosus (SLE), rheumatoid arthritis, myositis, systemic sclerosis and primary Sjögren's syndrome were the most studied RMDs. The literature demonstrated significant heterogeneity in techniques, analytical conditions, risk of bias and application in diseases. Inadequate study designs and technical heterogeneity were the main limitations. IFN-I pathway activation was associated with disease activity and flare occurrence in SLE, but their incremental value was uncertain. IFN-I pathway activation may predict response to IFN-I targeting therapies and may predict response to different treatments.

CONCLUSIONS

Evidence indicates potential clinical value of assays measuring IFN-I pathway activation in several RMDs, but assay harmonisation and clinical validation are urged. This review informs the EULAR points to consider for the measurement and reporting of IFN-I pathway assays.

CXCL9, 10, 11/CXCR3 Axis Contributes to the Progress of Primary Sjogren's Syndrome by Activating GRK2 to Promote T Lymphocyte Migration

Primary Sjogren's syndrome (pSS) is a systemic autoimmune disease that causes dysfunction of secretory glands and the specific pathogenesis is still unknown. The CXCL9, 10, 11/CXCR3 axis and G protein-coupled receptor kinase 2 (GRK2) involved in many inflammation and immunity processes. We used NOD/Ltj mice, a spontaneous SS animal model, to elucidate the pathological mechanism of CXCL9, 10, 11/CXCR3 axis promoting T lymphocyte migration by activating GRK2 in pSS. We found that CD4 + GRK2, Th17 + CXCR3 was apparently increased and Treg + CXCR3 was significantly decreased in the spleen of 4W NOD mice without sicca symptom compared to ICR mice (control group). The protein levels of IFN-γ, CXCL9, 10, 11 increased in submandibular gland (SG) tissue accompanied by obvious lymphocytic infiltration and Th17 cells overwhelmingly infiltrated relative to Treg cells at the sicca symptom occurs, and we found that the proportion of Th17 cells was increased, whereas that of Treg cells was decreased in spleen. In vitro, we used IFN-γ to stimulate human salivary gland epithelial cells (HSGECs) co-cultured with Jurkat cells, and the results showed that CXCL9, 10, 11 was increased by IFN-γ activating JAK2/STAT1 signal pathway and Jurkat cell migration increased with the raised of cell membrane GRK2 expression. HSGECs with tofacitinib or Jurkat cells with GRK2 siRNA can reduce the migration of Jurkat cells. The results indicate that CXCL9, 10, 11 significantly increased in SG tissue through IFN-γ stimulating HSGECs, and the CXCL9, 10, 11/CXCR3 axis contributes to the progress of pSS by activating GRK2 to promote T lymphocyte migration.

Phosphorylated signal transducer and activator of transcription proteins 1 in salivary glandular tissue: an important histological marker for diagnosis of primary Sjögren's syndrome

OBJECTIVES

The pathological diagnostic criteria for primary Sjögren's syndrome (SjS) have certain limitations. We first explored the key pathogenic pathways of SjS through a bioinformatics approach, and then evaluated the diagnostic value of the important biomarker in SjS.

METHODS

Transcriptome data from non-SjS controls and patients with SjS were analysed using integrated bioinformatics methods. In a case-control study, phosphorylated signal transducer and activator of transcription proteins 1 (p-STAT1), a key biomarker for the activation of interferon (IFN) pathway, was selected to evaluate its diagnostic value by immunohistochemical analyses in salivary gland (SG) tissues.

RESULTS

The IFN-related pathways were aberrantly activated in patients with SjS. Positive staining of p-STAT1 was detected in the SjS group, but not in non-SjS control group. There was a significant difference in the integrated optical density values of p-STAT1 expressions between the controls and the SjS groups, as well as between the controls and the SjS lymphatic foci-negative groups (p<0.05). The area under the curve of the receiver operating characteristic curve for p-STAT1 was 0.990 (95% CI 0.969 to 1.000). There was a significant difference in both accuracy and sensitivity of p-STAT1 compared with the Focus Score (p<0.05). The Jorden index for p-STAT1 was 0.968 (95% CI 0.586 to 0.999).

CONCLUSIONS

The IFN pathway is the key pathogenic pathway in SjS. p-STAT1 may serve as an important biomarker, in addition to lymphocytic infiltration, to diagnose SjS. Particularly in SG samples with negative lymphatic foci, p-STAT1 confers pathological diagnostic value.

Clinical and laboratory evaluation of sicca complaints: distinctive aspects of primary, secondary and non-Sjogren syndrome

Background

Sjögren Syndrome (SS) is a systemic autoimmune disease with a wide spectrum of manifestations that can lead to misdiagnosis. This study describes and compares demographic, clinical, serological, and histopathological data from subjects with SS and non-Sjögren Syndrome (NSS). It also details specific features within the primary SS (pSS) and secondary SS (sSS) groups identifying sub-groups.

Methods

The sample included individuals referred to an academic medical center in Brazil for investigation of SS from 2012 to 2020. Patients were retrospectively classified as primary SS (pSS), secondary SS (sSS), or NSS, based on the American-European Consensus Group criteria (AECG-2002), after multi-professional clinical and laboratory evaluation.

Results

A total of 676 individuals were screened and 510 (75.4%) completed the assessments; 198 patients were classified as pSS, 149 as sSS, and 163 as NSS. Symptoms and glandular dysfunction tests were similar in the groups. Concerning pSS, extraglandular manifestations were present in 59% of patients; the elderly had more dry symptoms and peripheral neurological disorders; and 2.5% developed non-Hodgkin lymphoma. In sSS, each overlap promoted distinct clinical and laboratory variants. Several alternative diagnoses were identified as a cause of sicca complex in NSS group.

Conclusions

The diagnosis of SS remains a challenge behind dryness. Up to 31% of the suspected cases had other conditions associated to the symptoms. Histopathological analysis of LSG and SSa determined the diagnostic. Aging in pSS and overlap disease in sSS were responsible for distinct phenotypes and characteristic sub-groups in SS.

Predisposing Factors, Clinical Picture, and Outcome of B-Cell Non-Hodgkin’s Lymphoma in Sjögren’s Syndrome

Among other systemic autoimmune diseases, primary Sjögren syndrome (pSS) bears the highest risk for lymphoma development. In pSS, chronic antigenic stimulation gradually drives the evolution from polyclonal B-cell expansion to oligoclonal/monoclonal B-cell predominance to malignant B-cell transformation. Thus, most pSS-related lymphomas are B-cell non-Hodgkin lymphomas (NHLs), with mucosa-associated lymphoid tissue (MALT) lymphomas predominating, followed by diffuse large B-cell lymphomas (DLBCLs) and nodal marginal zone lymphomas (NMZLs). Since lymphomagenesis is one of the most serious complications of pSS, affecting patients’ survival, a plethora of possible predisposing factors has been studied over the years, ranging from classical clinical, serological, hematological, and histological, to the more recently proposed genetic and molecular, allowing clinicians to timely detect and to closely follow-up the subgroup of pSS patients with increased risk for lymphoma development. Overall predisposing factors for pSS-related lymphomagenesis reflect the status of B-cell hyperactivity. Different clinical features have been described for each of the distinct pSS-related B-cell NHL subtypes. While generally pSS patients developing B-cell NHLs display a fairly good prognosis, outcomes in terms of treatment response and survival rates seem to differ depending on the lymphoma subtype, with MALT lymphomas being characterized by a rather indolent course and DLBCLs gravely affecting patients’ survival.

JAK/STAT Pathway Targeting in Primary Sjögren Syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune systemic disease mainly affecting exocrine glands and resulting in disabling symptoms, as dry eye and dry mouth. Mechanisms underlying pSS pathogenesis are intricate, involving multiplanar and, at the same time, interlinked levels, e.g., genetic predisposition, epigenetic modifications and the dysregulation of both immune system and glandular-resident cellular pathways, mainly salivary gland epithelial cells. Unravelling the biological and molecular complexity of pSS is still a great challenge but much progress has been made in recent years in basic and translational research field, allowing the identification of potential novel targets for therapy development. Despite such promising novelties, however, none therapy has been specifically approved for pSS treatment until now. In recent years, growing evidence has supported the modulation of Janus kinases (JAK) - signal transducers and activators of transcription (STAT) pathways as treatment strategy immune mediated diseases. JAK-STAT pathway plays a crucial role in autoimmunity and systemic inflammation, being involved in signal pathways of many cytokines. This review aims to report the state-of-the-art about the role of JAK-STAT pathway in pSS, with particular focus on available research and clinical data regarding the use of JAK inhibitors in pSS.

Ruxolitinib inhibits IFNγ-stimulated Sjögren's salivary gland MSC HLA-DR expression and chemokine-dependent T cell migration

OBJECTIVES

Sjögren's disease (SjD) is a systemic autoimmune disease characterized by focal lymphocytic infiltrate of salivary glands (SGs) and high SG IFNγ, both of which are associated with elevated lymphoma risk. IFNγ is also biologically relevant to mesenchymal stromal cells (MSCs), a SG resident cell with unique niche regenerative and immunoregulatory capacities. In contrast to the role of IFNγ in SjD, IFNγ promotes an anti-inflammatory MSC phenotype in other diseases. The objective of this study was to define the immunobiology of IFNγ-exposed SG-MSCs with and without the JAK1 & 2 inhibitor, ruxolitinib.

METHODS

SG-MSCs were isolated from SjD and controls human subjects. SG-MSCs were treated with 10 ng/ml IFNγ +/- 1000 nM ruxolitinib. Experimental methods included flow cytometry, RNA-sequencing, chemokine array, ELISA and transwell chemotaxis experiments.

RESULTS

We found that IFNγ promoted expression of SG-MSC immunomodulatory markers, including HLA-DR, and this expression was inhibited by ruxolitinib. We confirmed the differential expression of CXCL9, CXCL10, CXCL11, CCL2 and CCL7, initially identified with RNA sequencing. SG-MSCs promoted CD4+ T cell chemotaxis when pre-stimulated with IFNγ. Ruxolitinib blocks chemotaxis through inhibition of SG-MSC production of CXCL9, CXCL10 and CXCL11.

CONCLUSIONS

These findings establish that ruxolitinib inhibits IFNγ-induced expression of SG-MSC immunomodulatory markers and chemokines. Ruxolitinib also reverses IFNγ-induced CD4+ T cell chemotaxis, through inhibition of CXCL9, -10 and -11. Because IFNγ is higher in SjD than control SGs, we have identified SG-MSCs as a plausible pathogenic cell type in SjD. We provide proof of concept supporting further study of ruxolitinib to treat SjD.

A Temporal Comparative RNA Transcriptome Profile of the Annexin Gene Family in the Salivary versus Lacrimal Glands of the Sjögren's Syndrome-Susceptible C57BL/6.NOD-Aec1Aec2 Mouse

A generally accepted hypothesis for the initial activation of an immune or autoimmune response argues that alarmins are released from injured, dying and/or activated immune cells, and these products complex with receptors that activate signal transduction pathways and recruit immune cells to the site of injury where the recruited cells are stimulated to initiate immune and/or cellular repair responses. While there are multiple diverse families of alarmins such as interleukins (IL), heat-shock proteins (HSP), Toll-like receptors (TLR), plus individual molecular entities such as Galectin-3, Calreticulin, Thymosin, alpha-Defensin-1, RAGE, and Interferon-1, one phylogenetically conserved family are the Annexin proteins known to promote an extensive range of biomolecular and cellular products that can directly and indirectly regulate inflammation and immune activities. For the present report, we examined the temporal expression profiles of the 12 mammalian annexin genes (Anxa1-11 and Anxa13), applying our temporal genome-wide transcriptome analyses of ex vivo salivary and lacrimal glands from our C57BL/6.NOD-Aec1Aec2 mouse model of Sjögren's Syndrome (SS), a human autoimmune disease characterized primarily by severe dry mouth and dry eye symptoms. Results indicate that annexin genes Anax1-7 and -11 exhibited upregulated expressions and the initial timing for these upregulations occurred as early as 8 weeks of age and prior to any covert signs of a SS-like disease. While the profiles of the two glands were similar, they were not identical, suggesting the possibility that the SS-like disease may not be uniform in the two glands. Nevertheless, this early pre-clinical and concomitant upregulated expression of this specific set of alarmins within the immune-targeted organs represents a potential target for identifying the pre-clinical stage in human SS as well, a fact that would clearly impact future interventions and therapeutic strategies.

Biomarkers of lymphoma in Sjögren's syndrome: what's the latest?

INTRODUCTION

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease standing in the crossroads of autoimmunity and lymphomagenesis, characterized by chronic B-cell hyperactivity and ectopic lymphoid tissue neoformation, potentially driving lymphoid malignant transformation. Lymphoma development is considered the most serious complication of pSS.

AREAS COVERED: “

Old-classical" biomarkers (clinical, serological, hematological, and histological) validated in the past are analyzed under the perspective of recently published research. Biomarkers that have emerged during the last decade are subdivided to "old-new" and "newly proposed-novel" ones, including biomarkers pathophysiologically related to B-cell differentiation, lymphoid organization, and immune responses, identified in serum and tissue, both at genetic and protein level. Upcoming new imaging biomarkers, promising for further patient stratification, are also analyzed.

EXPERT OPINION

Salivary gland enlargement and cryoglobulinemia still remain the best validated "classical-old" biomarkers for lymphoma development. Though new biomarkers still need to be validated, some can be used for the identification of high-risk patients long before lymphoma diagnosis, some might be more relevant in distinct age subgroups, while others have an added value in the assessment of lymphoma remission or relapse. Future development of composite indices integrating old and recently proposed biomarkers could contribute to a more precise lymphoma prediction model.

Composition and regulation of the immune microenvironment of salivary gland in Sjögren’s syndrome

Primary Sjögren’s syndrome (pSS) is a systemic autoimmune disease characterized by exocrine gland dysfunction and inflammation. Patients often have dry mouth and dry eye symptoms, which seriously affect their lives. Improving dry mouth and eye symptoms has become a common demand from patients. For this reason, researchers have conducted many studies on external secretory glands. In this paper, we summarize recent studies on the salivary glands of pSS patients from the perspective of the immune microenvironment. These studies showed that hypoxia, senescence, and chronic inflammation are the essential characteristics of the salivary gland immune microenvironment. In the SG of pSS, genes related to lymphocyte chemotaxis, antigen presentation, and lymphocyte activation are upregulated. Interferon (IFN)-related genes, DNA methylation, sRNA downregulation, and mitochondrial-related differentially expressed genes are also involved in forming the immune microenvironment of pSS, while multiple signaling pathways are involved in regulation. We further elucidated the regulation of the salivary gland immune microenvironment in pSS and relevant, targeted treatments.

IRF9 and XAF1 as Diagnostic Markers of Primary Sjogren Syndrome

Objective. Primary Sjogren syndrome (pSS) is characterized by lymphocytic infiltration of the salivary and lacrimal glands. It is a chronic systemic autoimmune disease. Genetic contributions and disturbed biological systems are the two major causes of pSS, but its etiology is unclear. This study is aimed at identifying potential pSS diagnostic markers and mechanisms at the transcriptome level. Methods. Whole blood datasets of patients with pSS were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using the online tool, GEO2R. R software was used to perform enrichment analyses to understand the functions and enriched pathways of the DEGs. A protein–protein interaction network was constructed to identify hub genes and significant gene clusters. The least absolute shrinkage and selection operator logistic regression was used to screen pSS diagnostic markers. The expression level and diagnostic performance of the identified genes were tested using another GEO dataset. Results. A total of 221 DEGs were screened from the whole blood samples of 161 patients with pSS and 59 healthy controls. Functional enrichment analysis demonstrated that DEGs were mostly enriched in defense response to virus, response to virus, and type I interferon signaling pathway. Cytoscape identified 10 hub genes and two gene clusters. IRF9 ( $\text{AUC}=0.799$ ) and XAF1 ( $\text{AUC}=0.792$ ) were identified as pSS diagnostic markers. The expression levels of the two identified genes were validated by GSE51092. Conclusion. IRF9 and XAF1 were identified as diagnostic markers. The potential underlying molecular mechanism of pSS was explored.

Aberrant signaling of immune cells in Sjögren’s syndrome patient subgroups upon interferon stimulation

Background

Primary Sjögren’s syndrome (pSS) is a systemic autoimmune disease, characterized by mononuclear cell infiltrates in the salivary and lacrimal glands, leading to glandular atrophy and dryness. Patient heterogeneity and lack of knowledge regarding its pathogenesis makes pSS a difficult disease to manage.

Methods

An exploratory analysis using mass cytometry was conducted of MAPK/ERK and JAK/STAT signaling pathways in peripheral blood mononuclear cells (PBMC) from 16 female medication free pSS patients (8 anti-Sjögren’s syndrome-related antigen A negative/SSA- and 8 SSA+) and 8 female age-matched healthy donors after stimulation with interferons (IFNs).

Results

We found significant differences in the frequencies of memory B cells, CD8+ T central and effector memory cells and terminally differentiated CD4+ T cells among the healthy donors and patient subgroups. In addition, we observed an upregulation of HLA-DR and CD38 in many cell subsets in the patients. Upon IFNα2b stimulation, slightly increased signaling through pSTAT1 Y701 was observed in most cell types in pSS patients compared to controls, while phosphorylation of STAT3 Y705 and STAT5 Y694 were slightly reduced. IFNγ stimulation resulted in significantly increased pSTAT1 Y701 induction in conventional dendritic cells (cDCs) and classical and non-classical monocytes in the patients. Most of the observed differences were more prominent in the SSA+ subgroup, indicating greater disease severity in them.

Conclusions

Augmented activation status of certain cell types along with potentiated pSTAT1 Y701 signaling and reduced pSTAT3 Y705 and pSTAT5 Y694 induction may predispose pSS patients, especially the SSA+ subgroup, to upregulated expression of IFN-induced genes and production of autoantibodies. These patients may benefit from therapies targeting these pathways.

Differentiating central nervous system demyelinating disorders: The role of clinical, laboratory, imaging characteristics and peripheral blood type I interferon activity

Objective: While multiple sclerosis (MS) is considered the cornerstone of autoimmune demyelinating CNS disorders, systemic autoimmune diseases (SADs) are important MS mimickers. We sought to explore whether distinct clinical, laboratory, and imaging characteristics along with quantitation of peripheral blood type I interferon (IFN) activity could aid in differentiating between them.

Methods: A total of 193 consecutive patients with imaging features suggesting the presence of CNS demyelinating disease with or without relevant clinical manifestations underwent full clinical, laboratory, and imaging evaluation, including testing for specific antibodies against 15 cellular antigens. Expression analysis of type I IFN-inducible genes (MX-1, IFIT-1, and IFI44) was performed by real-time PCR, and a type I IFN score, reflecting type I IFN peripheral activity, was calculated. After joint neurological/rheumatological evaluation and 1 year of follow-up, patients were classified into MS spectrum and CNS autoimmune disorders.

Results: While 66.3% (n = 128) of the patients were diagnosed with MS spectrum disorders (predominantly relapsing–remitting MS), 24.9% (n = 48) were included in the CNS autoimmune group, and out of those, one-fourth met the criteria for SAD (6.7% of the cohort, n = 13); the rest (18.1% of the cohort, n = 35), despite showing evidence of systemic autoimmunity, did not fulfill SAD criteria and comprised the “demyelinating disease with autoimmune features” (DAF) subgroup. Compared to the MS spectrum, CNS autoimmune patients were older, more frequently females, with increased rates of hypertension/hyperlipidemia, family history of autoimmunity, cortical dysfunction, anti-nuclear antibody titers ≥1/320, anticardiolipin IgM positivity, and atypical for MS magnetic resonance imaging lesions. Conversely, lower rates of infratentorial and callosal MRI lesions, CSF T2 oligoclonal bands, and IgG-index positivity were observed in CNS autoimmune patients. Patients fulfilling SAD criteria, but not the DAF group, had significantly higher peripheral blood type I IFN scores at baseline compared to MS spectrum [median (IQR)]: 50.18 (152.50) vs. −0.64 (6.75), p-value: 0.0001.

Conclusion: Our study suggests that underlying systemic autoimmunity is not uncommon in patients evaluated for possible CNS demyelination. Distinct clinical, imaging and laboratory characteristics can aid in early differentiation between MS and CNS-involving systemic autoimmunity allowing for optimal therapeutic strategies. Activated type I IFN pathway could represent a key mediator among MS-like-presenting SADs and therefore a potential therapeutic target.

TAFRO syndrome: A severe manifestation of Sjogren's syndrome? A systematic review

BACKGROUND

Sjögren's syndrome (SjS) is a systemic autoimmune disease characterized by lymphocytic infiltration of the salivary and lacrimal glands associated with sicca syndrome. TAFRO syndrome is a systemic inflammatory disease of unknown cause, characterized by Thrombocytopenia, Anasarca, Fever, Reticulin fibrosis, Renal dysfunction and Organomegaly, first reported in 2010 in Japanese patients. Despite their rarity, both conditions have been concurrently reported in several patients during the recent years, hence questioning the existence of shared or related features.

METHODS

A systematic review of the literature regarding SjS associated with TAFRO syndrome (SjS-TAFRO) was performed. The 2019 updated Masaki diagnostic criteria were used for TAFRO syndrome and SjS was considered when the diagnosis was mentioned by the authors, necessarily with either anti-Sjogren's Syndrome A (SSA) ± anti-Sjogren's Syndrome B (SSB) antibodies and/or histological evidence of focal lymphocytic sialadenitis.

RESULTS

Ten cases of SjS-TAFRO have been reported in the literature to date. Compared to SjS patients without TAFRO syndrome, these 10 SjS-TAFRO had a lower female predominance (2.3:1 vs 9:1 women to man ratio) and a higher frequency of anti-SSA antibodies (90% vs 70%). All fulfilled the three major Masaki criteria i.e., anasarca, thrombocytopenia, and systemic inflammation. Seven of them (70%) had megakaryocyte hyperplasia or reticulin fibrosis in the bone marrow. Lymph node biopsy was performed in 8 out of 10 cases (80%) and results were consistent with Castleman disease in 6 (75%). Eight of them had developed renal failure (80%) within six months. Nine of them (90%) had organomegaly, with hepatosplenomegaly in 8 cases and splenomegaly alone in 1.

CONCLUSION

This review brings new insights regarding TAFRO syndrome and suggests it could be a severe manifestation of SjS. The identification of shared abnormal signaling pathways could help in the therapeutic management of both diseases, which face an unmet therapeutic need.

Multi-Omic Biomarkers for Patient Stratification in Sjogren's Syndrome-A Review of the Literature

Sjögren's syndrome (SS) is a heterogeneous autoimmune rheumatic disease (ARD) characterised by dryness due to the chronic lymphocytic infiltration of the exocrine glands. Patients can also present other extra glandular manifestations, such as arthritis, anaemia and fatigue or various types of organ involvement. Due to its heterogenicity, along with the lack of effective treatments, the diagnosis and management of this disease is challenging. The objective of this review is to summarize recent multi-omic publications aiming to identify biomarkers in tears, saliva and peripheral blood from SS patients that could be relevant for their better stratification aiming at improved treatment selection and hopefully better outcomes. We highlight the relevance of pro-inflammatory cytokines and interferon (IFN) as biomarkers identified in higher concentrations in serum, saliva and tears. Transcriptomic studies confirmed the upregulation of IFN and interleukin signalling in patients with SS, whereas immunophenotyping studies have shown dysregulation in the immune cell population frequencies, specifically CD4⁺and C8⁺T activated cells, and their correlations with clinical parameters, such as disease activity scores. Lastly, we discussed emerging findings derived from different omic technologies which can provide integrated knowledge about SS pathogenesis and facilitate personalised medicine approaches leading to better patient outcomes in the future.

Distinct type I interferon responses between younger women and older men contribute to the variability of COVID-19 outcomes: Hypothesis generating insights from COVID-19 convalescent individuals

Background/Objective

Older age and male sex have been consistently found to be associated with dismal outcomes among COVID-19 infected patients. In contrast, premenopausal females present the lowest mortality among adults infected by SARS-CoV-2. The goal of the present study was to investigate whether peripheral blood type I interferon (IFN) signature and interleukin (IL)-6 serum levels -previously shown to contribute to COVID-19-related outcomes in hospitalized patients- is shaped by demographic contributors among COVID-19 convalescent individuals.

Patients and Methods

Type I IFN-inducible genes in peripheral blood, as well as serum IL-6 levels were quantified in 61 COVID-19 convalescent healthy individuals (34 females, 27 males; age range 18–70 years, mean 35.7 ± 15.9 years) who recovered from COVID-19 without requiring hospitalization within a median of 3 months prior to inclusion in the present study. Among those, 17 were older than 50 years (11 males, 6 females) and 44 equal to or less than 50 years (16 males, 28 females). Expression analysis of type I IFN-inducible genes (MX-1, IFIT-1, IFI44) was performed by real time PCR and a type I IFN score, reflecting type I IFN peripheral activity, was calculated. IL-6 and C-reactive protein levels were determined by a commercially available ELISA.

Results

COVID-19 convalescent individuals older than 50 years exhibited significantly decreased peripheral blood type I IFN scores along with significantly increased IL-6 serum levels compared to their younger counterparts less than 50 years old (5.4 ± 4.3 vs 16.8 ± 24.7, p = 0.02 and 10.6 ± 16.9 vs 2.9 ± 8.0 ng/L, p = 0.03, respectively). Following sex stratification, peripheral blood type I IFN score was found to be significantly higher in younger females compared to both younger and older males (22.9 ± 29.2 vs 6.3 ± 4.6 vs 4.5 ± 3.7, p = 0.01 and p = 0.002, respectively). Regarding IL-6, an opposite pattern was observed, with the highest levels being detected among older males and the lowest levels among younger females (11.6 ± 18.9 vs 2.5 ± 7.8 ng/L, p = 0.03).

Conclusion

Constitutive higher type I IFN responses and dampened IL-6 production observed in younger women of premenopausal age, along with lower type I IFN responses and increased IL-6 levels in older males, could account for the discrete clinical outcomes seen in the two population groups, as consistently revealed in COVID-19 epidemiological studies.

The promise of precision medicine in rheumatology

Systemic autoimmune rheumatic diseases (SARDs) exhibit extensive heterogeneity in clinical presentation, disease course, and treatment response. Therefore, precision medicine - whereby treatment is tailored according to the underlying pathogenic mechanisms of an individual patient at a specific time - represents the 'holy grail' in SARD clinical care. Current strategies include treat-to-target therapies and autoantibody testing for patient stratification; however, these are far from optimal. Recent innovations in high-throughput 'omic' technologies are now enabling comprehensive profiling at multiple levels, helping to identify subgroups of patients who may taper off potentially toxic medications or better respond to current molecular targeted therapies. Such advances may help to optimize outcomes and identify new pathways for treatment, but there are many challenges along the path towards clinical translation. In this Review, we discuss recent efforts to dissect cellular and molecular heterogeneity across multiple SARDs and future directions for implementing stratification approaches for SARD treatment in the clinic.

CCL5 Release by CCR9+ CD8 T Cells: A Potential Contributor to Immunopathology of Primary Sjögren's Syndrome

Introduction

Increased CCL5 expression and CD8 T cells have been shown to be pivotal regulators of immunopathology in primary Sjögren’s syndrome (pSS) and pSS-like disease. Increased CCL5 expression by CCR9+ CD4 T cells has previously been implicated as a contributor to immunopathology in pSS. The role of CD8 T cells and in particular CCR9+ CD8 T cells and their potential to secrete CCL5 has not previously been studied in pSS. In this study we investigated both CCR9 and CCL5 expression by CD8 T cells in pSS patients compared to healthy controls (HC).

Methods

CCR9 expression on CD8 T cells from peripheral blood was compared between patients with pSS and HC by flow cytometry. Intracellular CCL5 expression by naive, memory and effector CCR9- and CCR9+ CD8 T cells was assessed. In addition, the capacity and pace of CCL5 release upon T cell activation was determined for all subsets and compared with CD4 T cells.

Results

The frequency of circulating CCR9+ CD8 T cells in pSS patients is increased compared to HC. Antigen-experienced CD8 T cells, especially CCR9+ effector CD8 T cells, express the highest CCL5 levels, and release the highest levels of CCL5 upon activation. Memory and effector CD8 T cells of pSS patients express significantly less CCL5 and subsequently release less CCL5 upon stimulation compared to HC. CCR9+ CD8 T cells rapidly release CCL5 and significantly more than CCR9+ CD4 T cells.

Conclusion

CCR9+ CD8 T cells express more CCL5 than CCR9- CD8 T cells. CCL5 is rapidly released upon activation, resulting in reduced intracellular expression. Reduced CCL5 expression by an elevated number of antigen-experienced CCR9-expressing CD8 T cells in pSS patients points towards increased release in vivo. This suggests that CCL5 release by CCR9+ CD8 T cells contributes to immunopathology in pSS.